package leecode.topic21;

import leecode.topic21.vo.ListNode;

/**
 * 将两个有序链表合并为一个新的有序链表并返回。新链表是通过拼接给定的两个链表的所有节点组成的。 
 *
 * 示例：
 *
 * 输入：1->2->4, 1->3->4
 * 输出：1->1->2->3->4->4
 *
 * 来源：力扣（LeetCode）
 * 链接：https://leetcode-cn.com/problems/merge-two-sorted-lists
 * 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。
 */
public class Topic21 {

    public static ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if(l1 == null && l2 != null){
            return l2;
        }
        if( l2 == null){
            return l1;
        }
        ListNode result = new ListNode(0);
        ListNode tmp = result;
        while (l1 != null && l2 != null){
            if(l1.val > l2.val){
                tmp.next = l2;
                l2 = l2.next;
            }else{
                tmp.next = l1;
                l1 = l1.next;
            }
            tmp = tmp.next;
        }
        if(l1 != null){
            tmp.next = l1;
        }
        if(l2 != null){
            tmp.next = l2;
        }
        return result.next;
    }

    public static void main(String[] args) {
        ListNode l1 = new ListNode(1);
        l1.next = new ListNode(2);
        l1.next.next = new ListNode(4);

        ListNode l2 = new ListNode(1);
        l2.next = new ListNode(2);
        l2.next.next = new ListNode(3);
        ListNode node =  mergeTwoLists(l1, l2);
        println(node);

    }


    private static void println(ListNode li ){
        ListNode node =  li;
        while (node != null){
            System.out.print(node.val);
            node = node.next;
        }
        System.out.println();

    }

}
